New research reveals that when red blood cells are hit with laser light, they produce high frequency sound waves that contain a great deal of information. Similar to the way one can hear the voices of different people and identify who they are, investigators reporting in the July 2 issue of Biophysical Journal, published by Cell Press, could analyze the sound waves produced by red blood cells and recognize their shape and size. The information may aid in the development of simple tests for blood-related diseases.